For the parameters used in Fig. REF , the interference effect changes the GW emission by roughly \(10\%\) . Including the interference in the evolution of the BH-condensate would not make much difference. Thus our conclusions in Sec.  still hold. Nonetheless, the beat-like pattern in the GW emission is a unique feature of those BH-condensate systems in which the subdominant mode has a mass larger than one percent of the dominant mode. It can be used to distinguish some BH-condensate systems from other monochromatic GW sources, supplementary to the frequency drift proposed in Refs. [1]}, [2]}.
<FIGURE>